How SIBO May Lead to Atherosclerosis

Research into how our gut effects our health continues to grow and grow every day. I’ve posted many articles related to this topic and continually stress the importance of gut health. Small Intestinal Bacterial Overgrowth (SIBO) is one such condition that seems to be very prominent in people suffering with digestive issues or “IBS”. Much of the conventional medical system is still not aware of SIBO and the effects it has, but the literature is quite clear here. The gut is important for many things, one of those being the production of vitamin K2 through the fermentation of fiber by our healthy bacteria in the large intestines.

K2 is a cofactor involved in carboxylation (activation) of several proteins such as the matrix Gla-protein (MGP) which is expressed in chondrocytes (cartilage), vascular smooth muscle and endothelial cells (blood vessels) and fibroblasts (connective tissue). This plays an important role in maintaining calcium status for arterial structure and function by regulating osteoblastic differentiation (bone formation). Increased levels of the inactive form of MGP is widely regarded as one of the best markers for low vitamin K2 status and has been known to be associated with the signs of early vascular disease and cardiovascular morbidity and mortality. Recent scientific literature now shows that changes within the arterial wall are a precipitating factor for atherosclerosis (not elevated cholesterol or triglycerides). One of the major changes within the vessel wall is calcification, thereby hardening the wall and making it more susceptible to damage.

Several diseases of the gastrointestinal tract, wherein gut bacteria act in a pathogenic capacity, are associated with vascular dysfunction and increase the risk of atherosclerosis in the host

When the gut is disrupted, such as in SIBO, the bacteria in the large intestine do not receive the nutrients they need to synthesize K2. This leads to a reduction in the carboxylation of MGP and an increase in calcium deposition of the arteries. SIBO has been shown to alter vitamin K metabolism in humans, which may therefore increase the risk of atherosclerosis and cardiovascular disease in this population. The study by Ponziani et al (2017) found a significant difference in the ratio of dephospho-uncarboxylated MGP (dp-ucMGP) in participants with SIBO vs controls. Interestingly, both groups had comparable intake of dietary K2 (between groups and against other European populations), suggesting the dietary intake of K2 does not correlate with dp-ucMGP levels. This suggests the importance of an intact microbiome to produce bioavailable K2 for MGP carboxylation and that this is the primary source of K2, not diet.

This study also showed a significant correlation between dp-cuMGP and PWV (pulse wave velocity), an ultrasound marker of arterial stiffness, without signs shown from cIMT. This suggests this may be a useful marker for screening the risk of atherosclerosis, before the formation of calcification and vessel wall changes.

Of course, more studies are needed to discover more about the connection between the gut, arterial dysfunction and cardiovascular disease. At any rate, if you suffer from any gut dysfunctions (gas, bloating, lethargy, fatigue, diarrhea, constipation), I highly recommend getting the adequate diagnostics and making the necessary lifestyle and dietary changes to reduce your odds of cardiovascular disease.

Book a consultation with me to learn what diagnostics to use and what dietary changes you can do to cure SIBO and improve cardiovascular health.